A hemicyanidin-based NIR fluorescent probe for detection of H₂S and imaging study in cells and mice

The selective detection of hydrogen sulfide in physiological and pathological processes has gained substantial attention in recent years. However, the real-time detection of hydrogen sulfide remains an elusive goal. In this work, a new type of hemicyanidin-based fluorescent "turn-on" probe NTR-HS (Ex = 680 nm, Em = 760 nm) was developed to detected H₂S in a very short time (3 min). The fluorescence quantum yield is 0.15 and accompanied with a noticeable color change from violet to blue that can be used to detect H₂S in the range 1.04 × 10⁻⁷–4 × 10⁻⁵ M with a limit of detection of 1.04 x 10^-7 M. The NTR-HS probe was also used for imaging of endogenous hydrogen sulfide and mitochondrial localization in HCT116 and HeLa cells. The detection mechanism was studied through fluorescence, UV–Vis, NMR, and mass analysis. Notably, the probe was successfully used to imaging H₂S in mice and locating hydrogen sulfide in the large intestine of mice. Graphical abstract: